1. Field of the Invention
The present invention relates to a data processing device and a power saving control method.
2. Related Background Art
Some kinds of conventional data processing devices respectively have two modes, that is, a normal mode and a power saving mode. Here, a print device which is representative of the conventional data processing device starts an operation in the normal mode when the power source thereof is turned on. Further, at the same time, the print device comes into an idle state which is equivalent to a print waiting state. Then, if the state that a print command by a computer terminal connected through an LAN or the like is not received continues for a predetermined time, the print device comes into the power saving mode for controlling power consumption (e.g., Japanese Patent Application Laid-Open No. H08-142458). Moreover, there is a print device which can externally set and change the time by which the device comes into the power saving mode (e.g., Japanese Patent Application Laid-Open No. 2003-246117).
Incidentally, as a kind of power saving mode, a deep sleep mode in which a specific information packet such as Magic Packet™ used for Wake On LAN in recent years is used is known.
In the deep sleep mode, even if the main power source of the data processing device is off, electricity (power) is being fed at all hours to the built-in LAN controller. For this reason, the LAN controller judges whether or not the data sequence corresponding to the inherent physical address set to the data processing device is incorporated in the specific information packet received through the LAN, and, when it is judged that the data sequence is incorporated in the received specific information packet, turns on the main power source. Thus, any electricity (power) is not fed to the circuits other than the LAN controller while the power saving mode is being set, whereby it is possible to more effectively control the power consumption.
In addition, there is a print device which judges whether or not to release a power saving mode based on the kind of received input data (e.g., Japanese Patent Application Laid-Open No. H08-142458). In the relevant print device, the power saving mode is not released in a case where the input data represents a status response command.
In the deep sleep mode, feed of electricity (power) to the data processing device is made lower as much as possible, whereby the effect of power saving is high.
Meanwhile, in case of enabling a computer terminal newly connected on the LAN to use the data processing device connected on the LAN due to installation of the device driver corresponding to the relevant data processing device, it is first necessary to enable the computer terminal to acknowledge all the data processing devices connected on the LAN so as to confirm what kinds of data processing devices being connected on the LAN. To achieve this, the specific information packet for releasing the deep sleep mode is often transmitted unconditionally to all the data processing devices.
Moreover, to acquire the current status information of the data processing device, the computer terminal often transmits the specific information packet for releasing the deep sleep mode to the relevant data processing device.
For these reasons, there is an occasion when the deep sleep mode of the data processing device is released even though any printing is not executed. Moreover, to cause the data processing device of which the deep sleep mode has been once released to come into the deep sleep mode again, it is necessary to wait for the elapse of a predetermined time previously set to each data processing device. Therefore, electric power is needlessly consumed as compared with the deep sleep mode.